Magnetic nanomaterials: Greener and sustainable alternatives for the adsorption of hazardous environmental contaminants

The global water resources have been considerably damaged by organic and inorganic pollutants generated as a result of fast urbanization and industrialization. Toxic contaminants in water pose a serious health threat to both humans and aquatic life. In terms of cost and performance, current remediation technologies are inadequate for eliminating low-concentration contaminants. Nanomaterials have unique advantages in this regard, including precisely adjustable surface areas, durability, and biocompatibility. Also, the surface functionalization of the nanoparticles can facilely be carried out to increase their selectivity and specificity towards a variety of pollutants. Among various nanomaterials the magnetic nanoparticles (MNPs) are promising class of nanomaterials due to their biocompatible, target-specific, easily regenerable, and reusable characters. They also feature simple separation techniques, high surface-to-volume ratios, and high adsorption rates. Based on these features their implication in wastewater treatment has dragged an enhanced amount of attention for the researchers. Therefore, MNPs provide a simple, low-maintenance alternative to traditional adsorbents for extracting contaminants from wastewater. Magnetic separation can reduce the environmental impact of MNPs in final effluents by managing the concentration of nanoadsorbents. MNPs are now in the development stage, however they are a promising treatment alternative for large-scale water treatment plants. The main objective of the present review is to focus on the efforts being carried out in the application of MNPs for the remediation of hazardous pollutants including organics, heavy metal ions, pharmaceutics, dyes, radioactive elements, and pathogens. Furthermore, the review present critical assessment and overview of a variety of magnetic nanomaterials and their applications to water and wastewater treatment. Finally, the feasibility of structure-property relationships, adsorption mechanisms, modeling for the removal of water pollutants, legality and toxicity, economic assessments, and future research directions for the complete utilization of MNPs are also discussed in detail.